Accurate perception of the three-dimensional (3D) structure of the environment is essential to daily function. 3D vision requires the brain to reconstruct the depth structure of the environment from the sequence of 2D retinal images arriving at the eyes. Most of our knowledge about the neural mechanisms of 3D vision is limited to the case of stationary observers viewing static surfaces; in contrast, objects typically move in depth and observers often need to judge 3D scene structure while they are also moving. To arrive at a deeper understanding of how the brain computes depth under dynamic viewing conditions, we need to elucidate the mechanisms by which visual neurons compute the motion of objects in depth, as well as the neural computations that underlie perception of depth from motion parallax cues that arise during self- motion. We propose a series of experiments that take important steps toward this more general understanding of the neural basis of depth perception. Aim #1 examines the mechanisms by which neurons signal motion-in-depth via binocular cues. Recent work established that neurons in area MT signal motion-in-depth based on both interocular velocity differences and changing disparity cues, but the mechanisms of this selectivity remain unknown. Aim #2 examines how global patterns of rotational optic flow resulting from observer movement are used by the brain to interpret depth from motion parallax. We hypothesize that these ?dynamic perspective? cues are encoded by neurons in area MSTd with very large receptive fields, and that these neurons also carry integrated efference copy signals regarding eye rotation. Aim #3 examines how extra- retinal signals related to eye and body rotation are combined and used to compute depth from motion parallax. At both neural and behavioral levels, we test a specific theoretically-motivated hypothesis for how eye and body rotation signals should be integrated to compute depth. A major strength of the proposed work is that it rigorously explores the interaction of multiple visual and extra-retinal signals in tightly-controlled experiments with clear theoretical predictions. The proposed research is directly relevant to the research priorities of the Strabismus, Amplyopia, and Visual Processing program at the National Eye Institute.